@Override
public final Expr comp(final QueryContext ctx) throws QueryException {
if (!test.comp(ctx)) return Empty.SEQ;
// leaf flag indicates that a context node can be replaced by a text() step
final Data data = ctx.data();
ctx.leaf =
data != null
&& test.test == Name.NAME
&& test.type != NodeType.ATT
&& axis.down
&& data.meta.uptodate
&& data.nspaces.size() == 0;
if (ctx.leaf) {
final Stats s = data.tagindex.stat(data.tagindex.id(((NameTest) test).ln));
ctx.leaf = s != null && s.leaf;
}
// as predicates will not necessarily start from the document node,
// the context item type is temporarily generalized
final Type ct = ctx.value != null ? ctx.value.type : null;
if (ct == NodeType.DOC) ctx.value.type = NodeType.NOD;
final Expr e = super.comp(ctx);
if (ct == NodeType.DOC) ctx.value.type = ct;
ctx.leaf = false;
// return optimized step / don't re-optimize step
if (e != this || e instanceof IterStep) return e;
// no numeric predicates.. use simple iterator
if (!uses(Use.POS)) return new IterStep(input, axis, test, preds);
// don't re-optimize step
if (this instanceof IterPosStep) return this;
// use iterator for simple numeric predicate
return useIterator() ? new IterPosStep(this) : this;
}
